1. Field of the Invention
The present invention relates to medical devices, and, in particular, to a retractor for harvesting a blood vessel, which, in turn, is used in connection with an ongoing or subsequent surgical procedure. More particularly, the present invention provides such a retractor that is capable of defining and illuminating a subcutaneous working space to ameliorate accessibility to, and to facilitate visualization and harvesting of one or more blood vessels (e.g., saphenous vein) for grafting/transplantation in connection with a surgical procedure (e.g., coronary bypass surgery).
2. Description of Related Art
In certain surgical procedures, it is necessary to remove a portion (or even the entirety) of a patient's blood vessel for use in another, often remotely located part of that, or a different patient's body. For example, it is known to remove/excise some or all of a patient's saphenous vein, cephalic vein, basilic vein, radial artery, or mammary artery for transplantation in connection with a coronary bypass surgical procedure. Once transplanted, the removed section (or entirety) of the vein/artery functions as a graft that replaces both the coronary arteries, which, as a result of aging and/or disease, have become blocked by plaque deposits, stenosis, or cholesterol, thus severely inhibiting their ability to supply life-sustaining blood to the patient's heart.
In some instances, these blockages can be treated with angioplasty, atherectomy or stent placement, and, therefore, coronary bypass surgery is not warranted. Quite often, however, a coronary bypass is required because these treatment methods are either contraindicated, or have proven incapable of removing such blockages from coronary arteries.
According to current coronary bypass surgery techniques, a blood vessel is harvested from elsewhere within a patient's body and grafted into a locus between the patient's aorta and the coronary artery beyond the point of blockage. It is preferred to use a blood vessel taken from the patient undergoing bypass surgery, since he/she is a ready source of suitable vessels that will not be rejected by his/her own body after transplantation.
Currently, the saphenous vein (which is located in a patient's leg) is the most commonly used graft/substitute for small arteries such as the coronary arteries. This is likely because the saphenous vein is typically 3 to 5 mm in diameter (i.e., about the same size as the coronary arteries), and further, because the venous system of the leg is sufficiently redundant, such that following removal of the saphenous vein, other veins that remain within the patient's leg are adequate to provide return blood flow.
Harvesting the saphenous vein entails making one or more incisions in a patient's leg, then using a retractor to reach beneath and lift the skin to expose underlying subcutaneous/connective tissue. This tissue is then pulled away to reveal the saphenous vein, which is then carefully removed.
Although handling of the saphenous vein should be kept to a minimum, it must be separated from the connective tissue, and that requires some contact with the vein. Thus, after the saphenous vein is exposed, medical personnel grasps it with their fingers while stripping off the surrounding tissues with dissecting scissors or other scraping instruments. The medical personnel then uses their fingers and/or blunt dissection tools to separate the vein from the surrounding tissue.
Once the saphenous vein has been completely separated from the surrounding tissue and the tributary veins that feed into the saphenous vein, medical personnel cut the proximal and distal end portions of the vein, and remove the vein from the leg. The saphenous vein is then prepared for implantation into the graft site, and the incision(s) made in the patient's leg is/are closed (e.g., by suturing or with staples).
Until recently, only one incision was made to access the saphenous vein. This incision was quite long—spanning a patient's groin to at least their knee, and often to their ankle.
Making this long, “filet-like” incision inherently presents a serious risk of injury to the medial lymph bundle and/or to nerves located within the patient's leg, as well as a realistic risk of infection to the incision site. Moreover, the healing process associated with this “filet-like” incision is quite protracted (often more prolonged than the healing time associated with the incision(s) made in the patient's chest in furtherance of the coronary bypass) and very painful, especially if the patient has circulation problems in their extremities. Ultimately, in fact, the incision often does not heal properly, and, in such instances, requires medical attention and/or an invasive procedure (e.g., corrective surgery) to enable proper healing thereof.
As indicated in U.S. Pat. No. 6,193,651 to DeFonzo, U.S. Pat. No. 6,228,025 to Hipps et al, and U.S. Pat. No. 6,322,499 to Evans et al., however, techniques now exist that allow the saphenous vein to be harvested by making several small (i.e., about 2.5 inches to 4 inches in length) transverse incisions on the proximal thigh, at the level of the knee joint, and, optionally, at the inner malleolus.
In accordance with these techniques, a retractor is inserted into each of these incisions to define, access and illuminate subcutaneous space. The retractor is used to form a skin bridge to allow for retraction of at least some of the fat and tissue surrounding the saphenous vein, which is then harvested according to, for example, the technique described above, but without the risks/drawbacks associated with making a “filet-like” incision.
Although such risks/drawbacks are avoided by making comparatively smaller incisions in connection with saphenous vein harvesting procedures, some in the art believe that other drawbacks—ones that were not prevalent when saphenous vein harvesting was performed by making the long, “filet-like” incision—can arise by virtue of making these small incisions and/or due to the design of the retractors used in connection with such procedures.
For example, some believe the harvesting process has become complicated by the need to utilize equipment that is small enough to fit into both these small incisions and the subcutaneous space. In particular, they believe that vessel harvesting equipment (e.g., a retractor) should have certain dimensions in order to easily and confidently manipulate a patient's skin and tissue, but also that it is currently not possible for the equipment to have such dimensions, and yet still be able to fit within these small incisions and the subcutaneous space.
One group of patients that would appear to be most affected by these alleged equipment-related limitations are obese patients. Because obese patients tend to have increased quantities of subcutaneous fat and/or tissue in their legs, it is perceived that equipment that is able to fit within small incisions cannot manipulate such fat and tissue to an extent that allows for proper visualization of the subcutaneous space.
Thus, the procedure for harvesting a saphenous vein from obese patients potentially creates a tradeoff that, at least in the minds of some, renders the procedure contraindicated for such patients. This is troubling because it suggests that the obese (who, at present, represent a significant percentage of those who require coronary artery bypass surgery) may have fewer options for vessels that may be harvested for grafting in connection with a coronary artery bypass procedure.
Yet another perceived problem with current techniques for the harvesting of vessels (e.g., the saphenous vein) is that some believe the design of retractors used in connection with harvesting techniques may impede optimal visualization of at least some of the subcutaneous space.
As noted above, such retractors are designed to reach beneath and lift a patient's skin to expose underlying, connective tissue and, in doing so, to create subcutaneous space near the vessel to be harvested.
For example, in furtherance of usage of the retractor (see FIG. 1) described and depicted in U.S. Pat. No. 6,228,025 to Hipps et al. to harvest a patient's saphenous vein, the retractor 210 is grasped at its handle 220, and placed within an incision in a patient's leg in a direction such that the proximal end 211 of the retractor enters the incision (and leg) first, followed by the remainder of its blade sections 230, 240.
Thus, when the retractor 210 is properly positioned beneath a patient's skin, the proximal end 211 of the retractor is located farthest (as compared to the remainder of the blade) from the incision. Once the retractor 210 has been inserted as such, the handle 220 is arched/lifted to, in turn, lift the entire blade, thus defining the subcutaneous space.
As described in U.S. Pat. No. 6,228,025 to Hipps et al., use of the retractor 210 allows for the creation and visualization of enough subcutaneous space to quickly and reliably perform vessel harvesting. Because of the design of the retractor 210, however, the entirety of this subcutaneous space might not be able to be optimally visualized. Most notably, the subcutaneous space defined at or near the proximal end 211 of the retractor 210 may be especially difficult to visualize. This is because the overlying skin and tissue tends to collapse atop and “flap over” the proximal end 211 of the retractor, thus potentially preventing optimal visualization of the area, especially if the patient is obese and, as such, has increased quantities of underlying tissue and/or fat.
Therefore, a need exists for surgical equipment, particularly a retractor, that is able to fit within the small incisions that are made in a patient in connection with minimally invasive vessel harvesting (e.g., saphenous vein or radial artery) and within the subcutaneous space that is defined under the patient's skin, but that also can easily and effectively manipulate a patient's underlying fat and/or tissue (even if the patient has abnormally large quantities thereof, e.g., if the patient is obese) and that can allow for increased visualization of the subcutaneous space defined by the retractor.